Where you live is also a huge factor. In New York City, my XL1200s costs me about $130 a month for full coverage, 25k/100k per accident limit and $500 deductible. In Virgina, the same bike and coverage used to cost $30 a month. I have never gotten a moving violation. Also, when I was paying VA rates, I was under 30. Now I'm 30, so get the rate break. If I were 29, the New Yrok policy would jump to $165 a month, with the same coverage.
Why? New York has a high rate of claims due to the crowded roads, crazy drivers, potholes big enough to tip you, etc. NYC and NJ also have some of the highest rates of insurance fraud in the country. This means that regardless of how safely I drive, the external factors in NY mean I am more likely to make a claim here than I would in VA. And, in fact my experience has been this is accurate. In my first 6 months in NY, my bike was knocked over twice (once into a parked car, breaking the steering lock, ignition module, bending the bars, and smashing my windscreen), some drunk idiot broke my windscreen for fun, someone set it on fire, and someone took a hammer to the gastank. For all of these incidents, it was parked. I only made a claim for the fire. And this is in a good neighborhood, too (83rd and 1st for those of you who know the City).
Had I made claims for all of these, the insurance company would have paid for the value of the bike several times over, and would have lost big money over the premium I paid.
Compare this to zero incidents in the 10 years of motorcycling prior to my moving to NY.
So, despite being a safe driver, responsible, etc., premiums reflect much more than your driving record.